1. Field of the Invention
The present invention relates to module boards.
2. Description of the Related Art
Module boards on which active elements, passive elements and integrated circuits are mounted are often required to increase mounting density by having components mounted on each side. That is, module boards are often required to be highly functional using a printed wiring board.
In general, in the case of adopting a structure where components are disposed on each side of a main board of the module board in order to increase the degree of integration of components mounted on the main board, it is difficult to directly and simply connect the main board to a motherboard of a surface-mounting type.
Therefore, the main board may be mounted on the motherboard by forming a recess for accommodating components mounted on one side of the main board in the motherboard or by using solder balls as terminals. Furthermore, as described in Japanese Laid-Open Patent Application No. 2004-303944, it has been proposed to electrically and mechanically connect the main board and the motherboard by providing a frame-shaped sub board between the main board and the motherboard to accommodate components on one side of the main board.